Back-Channel Etched In-Ga-Zn-O Thin-Film Transistor Utilizing Selective Wet-Etching of Copper Source and Drain

The electrical performance of the back-channel etched Indium–Gallium–Zinc–Oxide (IGZO) thin-film transistors (TFTs) with copper (Cu) source and drain (S/D) which are patterned by a selective etchant was investigated. The Cu S/D were fabricated on a molybdenum (Mo) layer to prevent the Cu diffusion to the active layer (IGZO). We deposited the Cu layer using thermal evaporation and performed the selective wet etching of Cu using a non-acidic special etchant without damaging the IGZO active layer. We fabricated the IGZO TFTs and compared the performance in terms of linear and saturation region mobility, threshold voltage and ON current (ION). The IGZO TFTs with Mo/Cu S/D exhibit good electrical properties, as the linear region mobility is 12.3 cm2/V-s, saturation region mobility is 11 cm2/V-s, threshold voltage is 1.2 V and ION is 3.16 × 10−6 A. We patterned all the layers by a photolithography process. Finally, we introduced a SiO2-ESL layer to protect the device from external influence. The results show that the prevention of Cu and the introduced ESL layer enhances the electrical properties of IGZO TFTs.

Capillary Driven Muilti Channels Microfluidic

The paper present design and fabrication of capillary driven muilti channels microfluidic. AutoCAD assisted layout design was conducted and fabricated based on cold photolithography process with precise geometry for capillary flow. The design was bonded with glass to test the flow and bonding integrity. The device was tested for flow and it was found the uniform capillary flow was established with strong bonding energy.

Research on Trench Etching and Photolithography Process of SiC Trench MOSFET

In this paper, the development of trench etching process and photolithography process for 6-inch 4H-SiC trench-type power MOSFET devices is mainly studied. Among them, the etching process successfully solved the anisotropy of dry etching of SiC, the different etching rates of different crystal planes, the difficulty of controlling the angle of the trench sidewall, and the easy formation of micro-trenches at the corners, etc. Successfully realized trenches with etch depth greater than 1.2um and sidewall angle greater than 90° in SiC. Subsequently, the trench was filled with SiO2 to achieve no holes in the trench after filling, and then the photolithography process was studied. Photolithography process is resolved at the trench coating, exposing and developing the non-uniformity problem, achieve a full and uniform coating, self-aligned trench overlay and the overlay accuracy of less than 0.1um, and there is no residue of photoresist in the groove after development. This article uses scanning electron microscope (SEM) to measure the morphology of the trench after etching and photolithography to characterize the experimental results, and the results meet the process requirements. The successful development of this process will facilitate the research and development of deeper trench-type power MOSFET devices.

Solderability and Reliability of Sintered Nano-Ag Bond Pads of Printed Re-Distribution Layer (RDL)

Re-distribution layer (RDL) is one key enabling technology for advance packaging. RDL is usually fabricated in wafer level by photolithography process. An alternative approach for implementing RDL by additive manufacturing (AM) method is proposed in this study. This allows RDL to be fabricated on singulation chip. Nano-silver (nano-Ag) ink is printed on the silicon chip to form routing traces and bond pads. However, the Ag pad may be consumed by solder quickly if the process is not properly controlled. This paper studied the effect of nano-Ag ink sintering condition on the solderability of Ag pad. The solder joint mechanical integrity was evaluated by solder ball shear test. High temperature storage test was also carried out to evaluate the solder joint reliability. Experiment results showed that Ag pad fabricated by AM is SMT compatible. High temperature storage did not cause early failure to the samples. There was not significant change in the Ag3Sn IMC layer thickness and mechanical strength. The finding of the present study will serve as a very useful reference for future practice of forming solder joints on sintered nano-Ag pads.

Back-channel Etched In-Ga-Zn-O Thin-film Transistor Utilizing Selective Wet-Etching of Copper Source and Drain

The electrical performance of the back-channel etched Indium–Gallium–Zinc–Oxide (IGZO) thin-film transistors (TFTs) with copper (Cu) source and drain (S/D) which are patterned by a selective etchant was investigated. The Cu S/D were fabricated on molybdenum (Mo) layer to prevent the Cu diffusion to the active layer (IGZO). We deposited the Cu layer using thermal evaporation and performed the selective wet etching of Cu using non-acidic special etchant without damaging the IGZO active layer. We fabricated the IGZO TFTs and compare the performance in terms of linear and saturation region mobility, threshold voltage and ON current (ION). The IGZO TFTs with Mo/Cu S/D exhibits good electrical properties as the linear region mobility is 12.3 cm2/V-s, saturation region mobility is 11 cm2/V-s, threshold voltage is 1.2 V and ION is 3.16 x 10-6 A. We patterned all the layers by photolithography process. Finally, we introduced SiO2-ESL layer to protect the device from the external influence. The results show that the prevention of Cu and introduced ESL layer enhances the electrical properties of IGZO TFTs.

Skin-Compatible Amorphous Oxide Thin-Film-Transistors with a Stress-Released Elastic Architecture

A highly reliable reverse-trapezoid-structured polydimethylsiloxane (PDMS) is demonstrated to achieve mechanically enhanced amorphous indium-gallium-zinc oxide (a-IGZO) thin-film-transistors (TFTs) for skin-compatible electronics. Finite element analysis (FEA) simulation reveals that the stress within a-IGZO TFTs can be efficiently reduced compared to conventional substrates. Based on the results, a conventional photolithography process was employed to implement the reverse-trapezoid homogeneous structures using a negative photoresist (NPR). Simply accessible photolithography using NPR enabled high-resolution patterning and thus large-area scalable device architectures could be obtained. The a-IGZO TFTs on the reverse-trapezoid-structured PDMS exhibited a maximum saturation mobility of 6.06 cm2V−1s−1 under a drain bias voltage of 10 V with minimal strain stress. As a result, the proposed a-IGZO TFTs, including stress-released architecture, exhibited highly enhanced mechanical properties, showing saturation mobility variation within 12% under a strain of 15%, whereas conventional planar a-IGZO TFTs on PDMS showed mobility variation over 10% even under a 1% strain and failed to operate beyond a 2% strain.

Study of the micro/nano-texture design to improve the friction properties of DLC thin films

In this study, a DLC pattern was fabricated through a photolithography process that constitutes a part of the semiconductor process, to investigate the frictional wear characteristics. The photolithography was used to produce negative patterns with a pattern width of 10 [Formula: see text]m or 20 [Formula: see text]m and a pattern depth of 500 nm on the DLC surface. The change in the coefficient of friction of the surface was investigated through a ball-on-disk tribology test on the fabricated micro/nano-sized DLC pattern. The DLC pattern fabricated by the photolithography process showed a superior coefficient of friction to that of the general DLC sample. These results show that the decrease in the surface friction coefficient of the patterned DLC thin film is due to the reduction in the surface contact area owing to the modification of the micro/nano-texture of the surface as well as the low friction characteristics of the DLC.

Patternable Quantum-Dot Photoresist with High Photolithographic Uniformity

We present a ligand-exchange-free photo-patternable quantum-dot photoresist (QDPR) with high photolithographic uniformity. The dispersion mechanism between the QD’s surface ligands and the functional groups of photoresist polymers are studied. Results show that the dispersibility and photoluminescent intensity of this QDPR can be both improved by controlling dispersant and antioxidant. For device demonstration, multi-colored quantum dot color conversion films (QDCCF) were prepared and patterned by a photolithography process. High QD dispersibility and film-forming uniformity were both achieved with this QDCCF. It is believed that the proposed QDPR has the potential to be extensively used in lighting or display applications.